Rainbow-electronics ATmega103L Manual do Utilizador descarregar pdf (Página 39)

ATmega603/103

The Stop condition provides a Timer Enable/Disable function. The CK down divided modes are scaled directly from the CK

CPU clock. If the external pin modes are used for Timer/Counter2, transitions on PD7/(T2) will clock the counter even if the

pin is configured as an output. This feature can give the user SW control of the counting.

Timer/Counter0 - TCNT0

Timer/Counter2 - TCNT2

These 8-bit registers contains the value of the Timer/Counters.

Both Timer/Counters are realized as up or up/down (in PWM mode) counters with read and write access. If the

Timer/Counter is written to and a clock source is selected, it continues counting in the timer clock cycle after it is preset with

the written value.

Table 12. Timer/Counter0 Prescale Select

CS02 CS01 CS00 Description

0 0 0 Timer/Counter0 is stopped.

001PCK0

010PCK0/8

011PCK0/32

100PCK0/64

1 0 1 PCK0/128

1 1 0 PCK0/256

1 1 1 PCK0/1024

Table 13. Timer/Counter2 Prescale Select

CS22 CS21 CS20 Description

0 0 0 Timer/Counter2 is stopped.

001CK

0 1 0 CK/8

011CK/64

1 0 0 CK/256

1 0 1 CK/1024

1 1 0 External Pin PD7(T2), falling edge

1 1 1 External Pin PD7(T2), rising edge

Bit 76543210

$32 ($42) MSB LSB TCNT0

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial value00000000

Bit 76543210

$24 ($44) MSB LSB TCNT2

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial value00000000

1 2 ... 34 35 36 37 38 39 40 41 42 43 44 ... 125 126

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Rainbow-electronics ATmega103L Manual do Utilizador Página 39